Definitely not, and not willing to do that either

 

I agree. The 997 will not give you the "rope" the 996 does. The AWD system is much more sensitive. On a 996 you need to stay within 4% of the same OD front to rear. On the 997, it should be more like 2%, and the rears have to be .5" taller than the front to be correct.

 

Damon, the % difference is one thing but what people keep overlooking is that, for example, a 2% larger rear than front is totally different than a 2% larger front than rear. On the 996tt, YOU MUST HAVE AN EVER SO SLIGHTLY LARGER FRONT THAN REAR DIAMETER for the viscous coupler to transfer torgue to the front. Either that or different final drive ratios which we do not have as both are 3.44.

 

[quote=JayAndreTT;3575039]Ask them to put in writing that this tire combo will work properly on the 996tt and not damage anything. They won't...
Ask them to explain to you how the mechanical AWD system with viscous coupler works on the 996tt. Deer in headlights look, guaranteed......

 

why dont we get Champion in here to Explain? ill PM them this Thread.

 

Yeah I wouldn't count on it either. So basically, the stock fronts are 225/40/18 and rears are 295/30/18. Would you recommend for a 19 inch wheels I just go 225/40/19 and 295/30/19? Is there still enough space in the well to drop the car a tad?

 

Yes, the above 225/40/19 and 295/30/19 will work and should not rub unless you have some funky offsets. The stock fronts are 25.1" and the stock rears are 25.0". As you can see, Porsche is using SLIGHTLY larger fronts. Pick a combo that will satisfy this simple requirement, either same size or tiny bit larger front. 19" wheels are a bit of a curse now since the 315/25/19 is no longer made. 235/35/19 (25.5") and 315/25/19 (25.2") was the proper size for AWD. Look at post #24, third paragraph, and you will see several combinations that will work properly with 19s. Your best bet is to stay with 18" wheels which will give you a number of options and better handling to boot. 19s are bling for the street, 18s are for performance....

 

With 18 inch wheels I can just stay at stock tire fitment right? (front at 225/40/18 and rear 295/30/18) I would want to reuse the Pilot Sports I have now on the stock wheels.

 

Yes, and you can also run 235/40/18 and 315/30/18 which works great. That's my track set up.

 

As much as people love to say the 997 sizes are fine, to include some dealerships, take heed to what these guys are saying. By the book, you're looking at close to a $10k repair with parts and labor through a dealership when that diff goes "POOF" > wobble wobble shake shake.

ask me how I know

 

Well I actually just lucked out. My friend will be buying my wheels since the fitment is perfect for 997tt! Offset is 44 for rear and 53 for front, is that okay for a 997tt?

 

that is good offset for 997tt

 

Are we safe to say 225/40/19 and 295/30/19 is an ideal setup aside from using 315 25 19 rears?

Any fitment issues in the wheel wells or just extremely close?

 

295 might be a Strech Fit on a 11.5 or 12" Wheel.

 

This cannot be true. Read the manual. Porsche recommends a winter tire size that has a larger rear diameter than the front.